NASHVILLE, Tenn. – President Donald Trump insisted anew on Tuesday that Mexico will pay for his proposed border wall and “enjoy it” as he tied Republican success in the November midterm elections to a continued focus on illegal immigration and border security.

Democrats are “bad at everything, but they’re good at sticking together” in Congress, Trump said as he campaigned for Rep. Marsha Blackburn, R-Tenn.

“In the end, Mexico is going to pay for the wall,” Trump said. “I’m telling you. I don’t want to cause any problem, but in the end Mexico is going to pay for the wall.”

Trump implied that Mexico is making concessions in the ongoing negotiations over continuation of the North American Free Trade Agreement but gave no details.

“They’re going to pay for the wall and they’re going to enjoy it,” Trump said.

Mexican President Enrique Peña Nieto responded late Tuesday by repeating that his country will “never” pay for the border wall. “President @realDonaldTrump: NO. Mexico will NEVER pay for a wall. Not now, not ever. Sincerely, Mexico,” Peña Nieto said on Twitter, according to Reuters.

In Tennessee, which went for Trump by 26 points in 2016, Blackburn is strongly emphasizing her support for Trump as she battles former Democratic governor Phil Bredesen to succeed Sen. Bob Corker, R-Tenn.

The crowd booed when Trump mentioned Corker, a sometime critic of Trump’s who is retiring.

In a rambling address lasting more than an hour, Trump returned frequently to the issue of illegal immigration and what he claimed is its link to crime and instability in the United States.

Though Trump has repeatedly talked about immigration in recent events – for instance, at roundtables in Washington, D.C., and on Long Island – he explicitly framed the issue in political terms Tuesday night, calling it a boon for Republicans in November.

“The Democrats want to use it as a campaign issue, and I keep saying I hope they do,” Trump said. Accusing Democrats of wanting “open borders,” Trump added: “That’s a good issue for us, not for them.”

He focused on the Central American and U.S. gang MS-13 and what he claimed is Democratic inaction to confront it, asking the crowd at one point to repeat his characterization of the gang as “animals.”

“The Democrats are lousy politicians,” Trump said. “They’re lousy on policy” but tend to vote as a bloc.

His immigration comments came as immigrant rights groups and Democratic lawmakers are raising an uproar over his administration’s most recent crackdowns on immigration, particularly a new “zero tolerance” policy that refers all illegal border crossings for criminal prosecution. Because children cannot be held with criminal suspects in jails, that forces the splitting up of families that show up at the border.

“You can say what you want, but I think border security and security in general is a great issue for the Republican Party,” Trump said.

“If you want your communities to be safe, if you want your schools to be safe, if you want your country to be safe, then you must go out and get the Democrats the hell out of office, because there’s no common sense,” Trump said.

“We’re going to defend our borders and we’re going to fight hard on crime,” Trump said, adding that “if the Democrats take over, you won’t have a Second Amendment.”

Blackburn enthusiastically espouses Trump’s hard-line immigration policies, touts his economic agenda and even has a style that is a bit Trumpian – confidently declaring in her debut campaign ad that she is “politically incorrect and proud of it.”

As Air Force One touched down here Tuesday afternoon, Blackburn – under a pink-and-purple umbrella in the misty Nashville, Tennessee, weather – was among the first to greet the president.

Yet this Senate race is causing some Republicans concern. In an interview with The Washington Post this month, Senate Majority Leader Mitch McConnell, R-Ky., named Tennessee one of the nine battleground states that will determine control of the Senate in November – ranking it higher than Ohio, Pennsylvania and Wisconsin, three states Trump won that have Democratic senators.

Corker has not helped matters for Republicans either; he has showered praise on Bredesen and vowed not to campaign against the former governor. But he supports Blackburn and has made the maximum contribution to her campaign.

The Real Clear Politics average of available polling in the race shows Bredesen with a five-point lead, but Blackburn’s allies have said any advantage for the former governor is due to his higher name recognition throughout the state. Blackburn is in her eighth term in the House, representing a western Tennessee district. Bredesen left office in 2011.

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